Specialised Service

Bathymetric Surveys

Survey-grade depth and volume data for dams, reservoirs, harbours and tailings facilities. USV multibeam capture, RTK positioning, SAGI-signed deliverables.

Trusted by
Sibanye-Stillwater Eskom Grindrod Debswana TotalEnergies
In short

A bathymetric survey maps the bed of a dam, reservoir, harbour, or pond using sonar from an uncrewed surface vessel. Delta Scan delivers depth models and volumes for capacity verification, dredging support, and tailings ponds, covering water too hazardous or large to wade.

Bathymetric survey is the underwater equivalent of topographic survey: measurement of the bed surface beneath a body of water. The applications are operationally important across multiple sectors. Reservoir capacity verification, dam silt accumulation tracking, harbour dredging planning, tailings dam pond volume, and water infrastructure condition assessment all require accurate bathymetric data, and traditional manned vessel surveys are slow, expensive, and limited in operating envelope.

Delta Scan operates unmanned surface vehicle (USV) bathymetric capture for inland and shallow coastal applications. The USV carries a multibeam echo sounder, RTK GNSS positioning, and motion reference unit for survey-grade bathymetric data. Capture is dense, repeatable, and safe in environments where a manned vessel survey would be impractical or expensive.

Selected output

Above and below the waterline.

Surface orthomosaics combined with sounding data for dam capacity, siltation, and coastal monitoring.

When to use it

Typical engagements.

Each scenario below represents a real-world trigger for this service. If your situation matches one of these, get in touch.

Dam and reservoir capacity verification

Operating capacity of dams declines over time due to siltation. Bathymetric survey establishes current capacity and trends, supporting water resource planning and abstraction licensing.

Tailings dam pond bathymetry

Tailings storage facility decant pond bathymetry, beach above-water survey, and freeboard calculation for GISTM-aligned monitoring.

Harbour and channel dredging

Pre and post-dredging bathymetric surveys for capital and maintenance dredging works. Volumetric verification of dredged quantity.

Water infrastructure condition

Submerged infrastructure inspection: dam wall submerged condition, intake structure condition, scour holes around bridges and weirs.

How it works

Our process.

A repeatable five-stage workflow. The same disciplined sequence runs whether the site is a 500-hectare mining operation or a single 60-metre bridge.

01

Site reconnaissance

Pre-survey reconnaissance covers vessel launch points, water level, current conditions, and any submerged hazards. Existing soundings or bathymetric records inform survey planning.

02

Survey planning

Survey line spacing is designed for the target resolution and the water depth. Cross-lines are planned for quality control. RTK base station and motion reference unit are established.

03

USV capture

The unmanned surface vehicle traverses the planned survey lines collecting multibeam echo sounder data. RTK GNSS provides positional accuracy; the motion reference unit corrects for roll, pitch, and heave.

04

Bathymetric processing

Raw sounder data is processed with sound velocity profiling, tide and motion corrections, and statistical outlier removal. Output is a dense, georeferenced point cloud of the bed surface.

05

SAGI signed deliverable

A signed survey report including bathymetric chart, bed surface DTM, contour plot, volumetric calculation for capacity or dredging applications, and accuracy statement. Delivered through DeltaCloud.

Request a bathymetric survey quote See GIS and topographic mapping
Equipment

What we use.

Calibrated, sector-matched hardware combined with proprietary software. The capture stack is selected for the asset, not the other way around.

Unmanned surface vehicle (USV)

Survey-grade USV with multibeam echo sounder, RTK GNSS, and motion reference unit. Capable of multi-hour autonomous survey missions.

Multibeam echo sounder

Survey-grade multibeam sonar for dense bed surface measurement. Sub-decimetre vertical accuracy in typical operating conditions.

RTK GNSS + IMU

Trimble RTK GNSS referenced to Trignet base. Motion reference unit (IMU) for vessel attitude correction. Combined sub-centimetre positional accuracy.

Sectors

Where this fits.

The same engineering discipline applies across Water infrastructure, Mining, Port and harbour, Municipal and civil. The detail changes with the asset class and the operational context.

Water infrastructure

Reservoir capacity verification, dam wall submerged condition, intake structure inspection, weir and abstraction structure surveys

Mining

Tailings storage facility decant pond bathymetry, paddock dam capacity verification, water management dam surveys

Port and harbour

Berth pocket dredging surveys, channel maintenance dredging, capital project pre and post-construction surveys

Municipal and civil

Storm water attenuation pond capacity, recreational dam capacity, scour assessment around civil structures

FAQ

Frequent questions.

Direct answers to the questions clients ask most often before engaging.

What accuracy can you achieve?

Vertical bed surface accuracy of 0.1 to 0.3 metres is typical in normal operating conditions. Tighter accuracy is achievable in calm, shallow conditions with optimised sounder configuration.

How shallow can you survey?

Multibeam survey is effective from approximately 0.5m depth upward. Very shallow areas (< 0.5m) require single beam or LiDAR bathymetric techniques, which we can deploy where commercially justified.

Can you survey turbid water?

Yes. Acoustic bathymetric methods are unaffected by water clarity. This is one of the key advantages over LiDAR or photogrammetric bathymetry in inland and harbour applications.

What about above-water survey integration?

Standard practice is to combine bathymetric (below water) with aerial photogrammetric (above water) survey to produce a continuous bed-to-bank model. The two datasets are co-registered through tide-corrected water-line surveys.

Do you work in saltwater and tidal environments?

Yes. Coastal and harbour work routinely includes tidal correction and saltwater sound velocity profiling. International deployments are scoped on a case basis.

Related services

If this fits, these often do too.

Engineering programmes rarely run on a single service. These adjacent capabilities most often pair with the work above.

Accuracy & standards

Built to be signed, not just shared.

Pr EngECSA 202001436

Every engineering deliverable is reviewed and signed by Darryl Epstein, a registered Professional Engineer (Pr Eng, ECSA 202001436).

SAGIsurvey

Geospatial deliverables carry registered land-surveyor sign-off where accuracy must be certified.

Classstated

Every deliverable carries a stated survey accuracy class or BIM level of development (LOD), reported per engagement against check-point analysis.

Standardscited

Findings cross-referenced to the applicable codes (SANS, TMH, EN), with accuracy statements on every report.

Start here

Request a bathymetric survey quote

Send the brief and our engineering team will review your enquiry and reply within one business day. Prefer to talk first? Call or WhatsApp us below.

Response within 1 business day · Pr Eng or SAGI signed

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